[PATCH v7 5/5] usb: xhci: provide a debugfs hook for erasing rom

Vinod Koul
2020-03-23T10:12:07Z

run "echo 1 > /sys/kernel/debug/renesas-usb/rom_erase" to erase firmware
when driver is loaded.

Subsequent init of driver shall reload the firmware

Signed-off-by: Vinod Koul <vkoul@kernel.org>
---
drivers/usb/host/xhci-pci-renesas.c | 35 +++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)

diff --git a/drivers/usb/host/xhci-pci-renesas.c b/drivers/usb/host/xhci-pci-renesas.c
index d43b3a76dff5..c1088b07dfa9 100644
--- a/drivers/usb/host/xhci-pci-renesas.c
+++ b/drivers/usb/host/xhci-pci-renesas.c
@@ -2,6 +2,7 @@
/* Copyright (C) 2019-2020 Linaro Limited */

#include <linux/acpi.h>
+#include <linux/debugfs.h>
#include <linux/firmware.h>
#include <linux/module.h>
#include <linux/pci.h>
@@ -162,6 +163,8 @@ static int renesas_fw_verify(struct pci_dev *dev,
return 0;
}

+static void debugfs_init(struct pci_dev *pdev);
+
static int renesas_check_rom_state(struct pci_dev *pdev)
{
u16 rom_state;
@@ -194,9 +197,11 @@ static int renesas_check_rom_state(struct pci_dev *pdev)
/* Check the "Result Code" Bits (6:4) and act accordingly */
switch (rom_state & RENESAS_ROM_STATUS_RESULT) {
case RENESAS_ROM_STATUS_SUCCESS:
+ debugfs_init(pdev);
return 0;

case RENESAS_ROM_STATUS_NO_RESULT: /* No result yet */
+ debugfs_init(pdev);
return 0;

case RENESAS_ROM_STATUS_ERROR: /* Error State */
@@ -450,6 +455,34 @@ static void renesas_rom_erase(struct pci_dev *pdev)
dev_dbg(&pdev->dev, "ROM Erase... Done success\n");
}

+static int debugfs_rom_erase(void *data, u64 value)
+{
+ struct pci_dev *pdev = data;
+
+ if (value == 1) {
+ dev_dbg(&pdev->dev, "Userspace requested ROM erase\n");
+ renesas_rom_erase(pdev);
+ return 0;
+ }
+ return -EINVAL;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(rom_erase_ops, NULL, debugfs_rom_erase, "%llu\n");
+
+static struct dentry *debugfs_root;
+
+static void debugfs_init(struct pci_dev *pdev)
+{
+ debugfs_root = debugfs_create_dir("renesas_usb", NULL);
+
+ debugfs_create_file("rom_erase", 0200, debugfs_root,
+ pdev, &rom_erase_ops);
+}
+
+static void debugfs_exit(void)
+{
+ debugfs_remove_recursive(debugfs_root);
+}
+
static bool renesas_download_rom(struct pci_dev *pdev,
const u32 *fw, size_t step)
{
@@ -761,6 +794,8 @@ int renesas_xhci_pci_probe(struct pci_dev *dev,

int renesas_xhci_pci_remove(struct pci_dev *dev)
{
+ debugfs_exit();
+
if (renesas_fw_check_running(dev)) {
/*
* bail out early, if this was a renesas device w/o FW.
--
2.25.1